1. Field of Invention
This invention relates to the door operating mechanisms for bins, boxes, shelters, vending kiosks, truck and trailer bodies, utility buildings, and the like where one or both sides are raised for access. In particular, operating mechanisms for raising gull-wing type doors hinged along a ridge pole in the center of the roof, and the like.    As a garage the invention provides convenient drive through capability.    As a transporter for recreational vehicles the invention is a very convenient roll-on roll-off drive through transport and storage unit.    As a storage building, the sides open for access by dolly, fork lift, wheelbarrow, and the like.    As bin, storage building, or vending kiosk, the raised open doors become eves to provide shelter from the weather.    As a truck or trailer body the sides open up for access.
2. Description of Prior Art
British Patent #GB 2,152,448 shows a truck body with a single gull-wing type side/roof panel door. GB 2,152,448 illustrates a hydraulic cylinder pin connected directly between the door and a fixed structure for opening a gull-wing lid/door. A pin connected hydraulic means is very common for lifting roof (lid) panels and side panels. The rotation at the attachment pins provides hinging for accommodating the changes of angle between the hydraulic cylinder and the structure as a door or lid is moved between closed and open positions. No additional mechanism to provide mechanical advantage and employed. The mechanism is simple, but requires the addition of a source of hydraulic pressure, which is seldom available in the applications for the present invention.
U.S. Pat. No. 4,268,084 uses a cable and pulley assembly with a spring as counterbalance for opening a folding gull wing lid/door plus a drop-side portion forming a ramp. The roof/door assembly is operated manually (Column 5, line 4) aided by the counter balancing forces from the spring and weight of the drop-side (ramp) which may be stepped on to complete the operation. '084 is not a true gull-wing, because the lid and side panel are hingedly connected. A counter arm guides the side panel motion. The whole assembly operates as a pin-connected trapezoid (FIG. 4). The roof/door mechanism described in '084 do not provide any sheltering to the workers or the truck contents from weather as does the present invention.
U.S. Pat. No. 6,890,020 shows a single roof with attached side closing means, in this case a canvas drop panel. '020 also shows the ubiquitous pin attached hydraulic cylinder as the opening mechanism. The lid/side assembly is not a gull-wing, but does open the side when the lid is raised. The similarity to the present invention ends there.
U.S. Pat. Nos. 6,896,316 and 6,902,226, both by William S. Taylor, show a single solid gull-wing door/lid structure hinged at the far side of the truck. It too uses the ubiquitous pin attached hydraulic cylinder as the opening mechanism (FIGS. 2 & 3b). The lid/side doors of '316 and '226 would be too heavy to be practical for using manual or low voltage electric motor lifting.
U.S. Pat. No. 4,682,811 is a multi-mode hinging for side and top doors of a box bin. One of the modes is a gull-wing lid/side door hinged at or near the center of the lid area (FIGS. 2 and 3a). '811, like others, is operated by pin attached hydraulic cylinders. '811 has no sealing means along the hinge lines to prevent ingress of rain or wash water.
Hydraulic lifting means, besides requiring a hydraulic power source, have several other disadvantages. When pinned between fixed and moving structures as illustrated in the above references, the angles of force during some of the range of motion are far from optimum. Indeed, the cylinder has to provide several times as much force in some positions as is required in other positions of the range of motion. Thus the cylinder has to be sized much larger and have more pressure to provide lift from this awkward configuration than is necessary for working over most of the range of motion. When hydraulic cylinders are used in tandem such as one on each end of the lid assembly as is also illustrated in the references, all the cylinders generally receive the same pressure from the power source, causing them to operate with coordinated (equal) force. If one portion of the moving structure requires more force to move, such as may be the case with snow load, damaged or rusty hinges, bending, dents, etc, the moving structure will be lifted unevenly, perhaps doing even more damage to the structure.
The present invention does not require an often absent source of hydraulic power, and the several lifting jacks are operated with coordinated movement, not coordinated force. Thus the gull-wing roof lifts evenly along its whole length.